A voltage is applied across a nanopore that is filled with electrolyte, resulting in an ionic current. As particles translocate through the nanopore they briefly increase electrical resistance, creating a transient resistive pulse, with its magnitude being proportional to particle volume.
TRPS is an impedance-based system. No lasers are involved.
The particle flow rate is proportional to particle concentration, so it can be accurately obtained at the same time as individual particle sizes. A core principle of TRPS is that the particle number and accurate particle size distribution are provided simultaneously.
TRPS enables simultaneous particle size and zeta potential measurements.
As particles pass through the nanopore they do so with a velocity that can be controlled and measured. While the depth (magnitude) of the resistive pulse is proportional to particle volume, the duration (pulse width) is a function of particle surface charge and zeta potential.
Particle-by-particle measurements as they pass through the nanopore are achieved through the use of calibration particles that have been certified for size, concentration and zeta potential.
TRPS is the only technology that delivers:
- Concentration of particles as a number of particles per unit volume of fluid, across a specified particle size range.
- Accurate size distribution of these particles plotted as a histogram of concentration v particle diameter (or volume).
- Simultaneous particle size and surface charge/zeta potential measurements on a particle by particle basis.